Bicomponent fiber

ABSTRACT

The present invention relates to a new bicomponent fiber, a nonwoven fabric comprising said new bicomponent fiber and sanitary articles made therefrom. The bicomponent fiber contains a polyethylene-based resin forming at least part of the surface of the fiber longitudinally continuously and is characterized by a Co-monomer Distribution Constant greater than about 45, a recrystallization temperature between 85° C. and 110° C., a tan delta value at 0.1 rad/sec from about 15 to 50, and a complex viscosity at 0.1 rad/second of 1400 Pa·sec or less. The nonwoven fabric comprising the new bicomponent fiber according to the instant invention are not only excellent in softness, but also high in strength, and can be produced in commercial volumes at lower costs due to higher thoughputs and requiring less energy.

RELATED APPLICATION

This application is a divisional application of U.S. Ser. No. 12/651,628filed Jan. 4, 2010, now U.S. Pat. No. 8,389,426.

BACKGROUND OF THE INVENTION

The present invention relates to a new bicomponent fiber, a nonwovenfabric comprising said new bicomponent fiber and sanitary articles madetherefrom. The nonwoven fabric comprising the new bicomponent fiberaccording to the instant invention are not only excellent in softness,but also high in strength, and can be produced in commercial volumes atlower costs due to higher thoughputs and requiring less energy.

Nonwoven fabrics, such as spunbonded nonwoven fabrics and Nonwovenfabrics manufactured using carding, melt-blowing or airlaid techniqueshave been used in a wide variety of applications recent years, also forsanitary articles made therefrom.

A polyethylene nonwoven fabric, which resin fibers are formed ofpolyethylene, is known for its softness and good touch (EP-A-0,154,197).Polyethylene fibers are, however, difficult to spin, and hence difficultto allow to have a fine denier which are required for obtaining a goodsoftness of a fabric. Nonwoven fabric formed of polyethylene fiberseasily melts when subjected to heat/pressure treatment with a calenderroll, and what is even worse, it easily winds itself around the roll dueto low strength of the fibers. Measures have been taken against theabove problems in which the treatment temperature is decreased; however,in such a case, thermal adhesion is apt to be insufficient, which leadsto another problem of being unable to obtain nonwoven fabric withsufficient strength and fastness to rubbing. In actuality, apolyethylene nonwoven fabric is inferior to a polypropylene nonwovenfabric in strength.

In order to solve the above mentioned problems, there, have beenproposed techniques of utilizing a core-sheath-type bicomponent fiberusing a resin of polypropylene, polyester, etc., as a core, andpolyethylene as a sheath (Japanese Patent Laid-Open No. 2-182960 andJapanese Patent Laid-Open No. 5-263353).

However, nonwoven fabrics, which are formed of core-sheath-typebicomponent fibers, as described above, have not had both softness andstrength adequate to be used as sanitary materials. Specifically, whenincreasing the amount of polyethylene as a constituent of sheath, thesoftness of the nonwoven fabric is enhanced, but its strength is notallowed to be sufficient, as a result of which it is likely to fractureduring the process. On the other hand, when increasing the constituentof core, the nonwoven fabric is allowed to have sufficient strength, butis poor in softness and its quality, as a material for sanitary goods,decreases. Thus it has been difficult to obtain a nonwoven fabric havingboth of the above performances on a satisfactory level.

Many of these core-sheath-type bicomponent fibers comprise apolyethylene sheath with a polyester or polypropylene core. Theincumbent polyethylenes typically used in such applications haverecrystallization temperatures which are generally greater than 110° C.

A first solution to the aforementioned problem is disclosed inEP-A-1,057,916 which describes spunbonded nonwoven fabrics fordisposable sanitary articles made from conjugated fibers. Suchconjugated fibers having a high melt core and low melt sheath materialcan be of side-by-side type. The low melt material proposed is apolyethylene based resin having a first high melting point in the rangeof 120 to 135° C. and a second low melting point in the range from 90 to125° C., the melting point of the second low melting material being atleast 5° C. below the first high melting point. Such low meltpolyethylene based resins are rather complex to make and cause problemsduring fiber spinning and later use of such conjugated fibers in theproduction of Nonwoven, in particular for Nonwoven fabrics manufacturedusing carding, melt-blowing or airlaid techniques.

However, it still would be desirable to lower the melting point of thepolyethylene in order to allow faster line speeds due to lower bindingtemperature and lower energy usage. On the other hand, lowering themelting point of the polyethylene is associated with significantprocessing problems during fiber spinning. For widespread applicabilityfor use in binder fibers, such fiber should have the followingcharacteristics: good spinning performance, such that smoke, fiberbreaks and fibers sticking together are minimized during the spinningprocess; the fibers also need to have a low COF to allow the ability tobe texturized; good fiber tensile properties; ability to be readily cut;ability to be used in the airlaid process and ability to be bonded usingthe thermal air bonding process at the lowest temperature without fibersbecoming sticky. Additionally, the outer layer of the bi-component fibershould have good bonding to the inner core (substrate) as well as toother fibrous products.

SUMMARY OF THE INVENTION

Accordingly, the object of the present invention is to solve theaforementioned problem, in particular, to provide a bicomponent fiberwhich provides a nonwoven fabric with excellent softness and touch aswell as with sufficient strength and which can be produced on existingcommercial equipment at lower costs.

The subject matter of the instant invention is directed to a bicomponentfiber composed of a polyethylene-based resin (A) and a high-meltingpoint resin (B) whose melting point is higher than that of the abovepolyethylene-based resin (A) by at least 10° C., the component ratio byweight of the polyethylene-based resin (A) to the high-melting pointresin (B) being in the range of 50/50 to 10/90, and thepolyethylene-based resin (A) forming at least part of the surface of thefiber longitudinally continuously wherein the polyethylene-based resin(A) is characterized by a Co-monomer Distribution Constant greater thanabout 45, a recrystallization temperature between 85° C. and 110° C., atan delta value at 0.1 rad/sec from about 15 to 50, and a complexviscosity at 0.1 rad/second of 1400 Pa·sec or less.

Further subjects of the instant invention are Nonwoven fabricscomprising bicomponent fibers as described above. Preferably suchNonwoven fabrics comprise the bicomponent fibers according to theinstant invention as texturized crimped fiber and/or non-texturized flatfibers. Further, such Nonwoven comprises the aforementioned bicomponentfibers as staple fiber and/or continuous filament fiber.

Preferred Nonwoven fabrics are (i) wet-laid Nonwoven, (ii) air-laidNonwoven and (iii) carded Nonwoven.

Another subject of the instant invention is a sanitary articlecomprising the Nonwoven fabrics according to the instant invention.

DESCRIPTION OF THE DRAWING

FIG. 1 is a graph illustrating dW/dT as a function of Temperature (° C.)and Cumulative Wt. Fraction as a function of Comonomer Content (mol %).

DESCRIPTION OF THE INVENTION Definitions

The term “composition” as used, includes a mixture of materials whichcomprise the composition, as well as reaction products and decompositionproducts formed from the materials of the composition.

The terms “blend” or “polymer blend,” as used, mean an intimate physicalmixture (that is, without reaction) of two or more polymers. A blend mayor may not be miscible (not phase separated at molecular level). A blendmay or may not be phase separated. A blend may or may not contain one ormore domain configurations, as determined from transmission electronspectroscopy, light scattering, x-ray scattering, and other methodsknown in the art. The blend may be effected by physically mixing the twoor more polymers on the macro level (for example, melt blending resinsor compounding) or the micro level (for example, simultaneous formingwithin the same reactor).

The term “long chain branched polymer” refers to polymers where polymerbackbone of the polymer contains branches that are longer than thetypically used co-monomers (for example longer than 6 or 8 carbonatoms). A long chain branched polymer typically contains more than 0.2long chain branches per 1000 carbon atoms.

The term “linear” refers to polymers where the polymer backbone of thepolymer lacks measurable or demonstrable long chain branches, forexample, the polymer can be substituted with an average of less than0.01 long branch per 1000 carbons. The term “polymer” refers to apolymeric compound prepared by polymerizing monomers, whether of thesame or a different type. The generic term polymer thus embraces theterm “homopolymer,” usually employed to refer to polymers prepared fromonly one type of monomer, and the term “interpolymer” as defined.

The term “interpolymer” refers to polymers prepared by thepolymerization of at least two different types of monomers. The genericterm interpolymer includes copolymers, usually employed to refer topolymers prepared from two different monomers, and polymers preparedfrom more than two different types of monomers.

The term “ethylene-based polymer” refers to a polymer that contains morethan 50 mole percent polymerized ethylene monomer (based on the totalamount of polymerizable monomers) and, optionally, may contain at leastone co-monomer.

Bicomponent Fiber

The bicomponent fiber of the instant invention can be of any shape andis not limited to a particular shape. However, preferred arecore-sheath-type bicomponent fibers and side-by-side-type bicomponentfibers.

Resin (A) Polyethylene-Based

The bicomponent fiber of the instant invention contains apolyethylene-based resin (A) which has a Co-monomer DistributionConstant greater than about 45, a recrystallization temperature between85° C. and 110° C., a tan delta value at 0.1 rad/sec from about 15 to50, and a complex viscosity at 0.1 rad/second of 1400 Pa·sec or less.

The ethylene-based polymer resin compositions can be furthercharacterized as having a single differential scanning calorimetry (DSC)melting peak within the temperature range from 85° C. to 110° C.

The ethylene-based polymer resin compositions can be furthercharacterized as having a Co-monomer Distribution Constant greater thanabout 45, more preferably greater than 50, most preferably greater than55, and as high as 400, more preferably as high as 100. In particularpreferred ethylene-based polymer resin compositions have a Co-monomerDistribution Constant in the range of 45 to 400, most preferred in therange of 50 to 100, at most preferred in the range of 55 to 100.

The ethylene-based polymer compositions are those made in high pressurereactors utilizing free radical polymerization process preferably usingperoxide based free radical initiators The preferred polyethylene resinshave a melt index (measured in accordance with ASTM D 1238, Condition190° C./2.16 kg) in the range of from 5 to 25 g/10 min, more preferably5 to 20.

Preferred ethylenic resins have a density in the range of from 0.910 to0.930 g/cm³, more preferably 0.915 to 0.925.

The ethylene based polymer compositions can also be characterized inhaving peak recrystallization temperature in the range of from 85° C. to110° C., preferably from 90 to 105° C.

The ethylene based polymer compositions can also be characterized byhaving more than about 0.2 long chain branches/1000 carbons, preferablyfrom about 0.2 to about 3 long chain branches/1000 carbons.

The ethylene based polymer compositions can also be characterized inhaving a complex viscosity at 0.1 rad/second of 1400 Pa·sec or less, andpreferably at 100 rad/seconds of 500 Pa·sec or less. Most preferably,the resins of the present invention will have a complex viscosity at 0.1rad/second in the range of 500 to 1200 and at 100 rad/seconds in therange of from 150 to 450 Pa·sec.

The preferred ethylene based polymer compositions can also becharacterized in having a Tan delta value at 0.1 rad/sec from about 15to 50, preferably 15 to 40.

In some processes for producing the polyethylene-based resin (A),processing aids, such as plasticizers, can also be included in theethylene based polymers of the present invention. These aids include,but are not limited to, the phthalates, such as dioctyl phthalate anddiisobutyl phthalate, natural oils such as lanolin, and paraffin,naphthenic and aromatic oils obtained from petroleum refining, andliquid resins from rosin or petroleum feedstocks. Exemplary classes ofoils useful as processing aids include white mineral oil such as KAYDOLoil (Chemtura Corp.; Middlebury, Conn.) and SHELLFLEX 371 naphthenic oil(Shell Lubricants; Houston, Tex.). Another suitable oil is TUFFLO oil(Lyondell Lubricants; Houston, Tex.).

In some processes, ethylenic polymers are treated with one or morestabilizers, for example, antioxidants, such as IRGANOX 1010 and IRGAFOS168 (Ciba Specialty Chemicals; Glattbrugg, Switzerland).

In general, polymers are treated with one or more stabilizers before anextrusion or other melt processes. In other embodiment processes, otherpolymeric additives include, but are not limited to, ultraviolet lightabsorbers, antistatic agents, pigments, dyes, nucleating agents,fillers, slip agents, fire retardants, plasticizers, processing aids,lubricants, stabilizers, smoke inhibitors, viscosity control agentssurface modification and anti-blocking agents. The ethylenic polymercomposition may, for example, comprise less than 10 percent by thecombined weight of one or more additives, based on the weight of theembodiment ethylenic polymer.

The ethylenic polymer produced may further be compounded. In someethylenic polymer compositions, one or more antioxidants may further becompounded into the polymer and the compounded polymer pelletized. Thecompounded ethylenic polymer may contain any amount of one or moreantioxidants. For example, the compounded ethylenic polymer may comprisefrom about 200 to about 600 parts of one or more phenolic antioxidantsper one million parts of the polymer. In addition, the compoundedethylenic polymer may comprise from about 800 to about 1200 parts of aphosphite-based antioxidant per one million parts of polymer.

The polyethylene-based resin (A) can be made using two or more reactors,one of which is a back mixed reactor with at least one reaction zone anda second reactor which is a laminar flow reactor with at least tworeactions zones. The product can also advantageously be made in atypical tubular high pressure process with two or more reaction zoneswith ethylene pressure at the inlet in the range of 1800 bars to 3500bars. The pressure at the inlet of the first reaction zone canadvantageously be in the range of from 2000 bars to 3000 bars. The startof polymerization temperature can be from 110° C. to 150° C. with thepeak temperature from about 280° C. to 330° C. For the initiation of thereaction, a mixture of peroxides was used to achieve the desiredreaction rate at a given temperature and pressure as is known in theart. The exact composition of the free radical peroxide initiatormixture can be determined based on the details of plant, processpressures, temperatures and residence times by those skilled in the art.For the production of the compositions of the present invention amixture of tertiary butyl peroctoate and ditertiary butyl peroxide canadvantageously be used in the first zone of the reactor in a ratio onthe order of 14 to 3 based on volume. The same two peroxides can alsoused in the second reaction zone at a volume ratio of 1 to 1. The exactamounts will depend on the purity of reactors, the reactorcharacteristics and other process parameters and can be determined foreach specific set up by those skilled in the art.

The second zone re-initiation temperature can be from about 160° C. to230° C. with a peak temperature of from about 280° C. to 330° C. Amixture of methyl ethyl ketone and propylene can be used as chaintransfer agent to control the molecular weight. The typical ranges canbe from about 10 to 5000 volume ppm of methyl ethyl ketone and fromabout 0.1 volume % to 5 volume % propylene depending on the complexviscosity ranges desired Then the polymer was separated from processsolvents and unreacted ethylene, palletized through an extruder and usedwithout further processing.

Additives and adjuvants may also be added to the ethylenic polymerpost-formation. Suitable additives include fillers, such as organic orinorganic particles, including clays, talc, titanium dioxide, zeolites,powdered metals, in particular based on silver and/or silver ions,superabsorber materials, organic or inorganic fibers, including carbonfibers, silicon nitride fibers, steel wire or mesh, and nylon orpolyester cording, nano-sized particles, clays, and so forth;tackifiers, oil extenders, including paraffinic or napthelenic oils; andother natural and synthetic polymers, including other polymers that areor can be made according to the embodiment methods.

Resin (B) High-Melting Point Resin

The bicomponent fiber of the instant invention contains a high-meltingpoint resin (B), typically forming the core portion of thecore-shear-type bicomponent fiber according to the present invention.Such high-melting point resin (B) is a thermoplastic resin having amelting point higher than that of the above polyethylene-based resin (A)by at least 10° C., preferably at least 20° C., most preferably at least30° C.

Preferred high-melting point resins (B) include polyolefin resins suchas propylene-based polymers, polyester resins such as polyethyleneterephthalate (PET) and polyamide resins such as nylon. Among all theabove resins, polyester resins such as polyethylene terephthalate (PET),polybutylene terephthalate (PBT) polynaphthalene terephthalate (PEN) aremost preferred.

Among the aforementioned propylene-based polymers, propylene homopolymeror copolymers of propylene and alpha-olefin, such as ethylene, 1-butene,1-hexene, 4-methyl-1-pentene and 1-octene are most preferred. Among allthe above copolymers, particularly preferable are propylene-ethylenerandom copolymer comprised of propylene and a small amount of ethylenewhose ethylene-derived structural unit content is 0.1 to 5 mol %. Theuse of copolymer of this type provides good spinnability andproductivity of their bicomponent fibers and a nonwoven fabric havinggood softness. The term “good spinnability” used herein means thatneither yarn breaking nor filament fusing occurs during extrusion fromspinning nozzles and during drawing.

Preferably the aforementioned propylene-based polymers have a melt flowrate (MFR; measured at 230° C. and at a load of 2.16 kg in accordancewith ASTM D1238) in the range of 20 to 100 g/10 min in terms ofobtaining a fiber particularly excellent in balance of spinnability andfiber strength.

Preferably the molecular weight distribution (Mw/Mn) of theaforementioned propylene-based polymers, when measuring by the gelpermeation chromatography (GPC), is in the range of 2.0 to 4.0, and morepreferably the Mw/Mn is in the range of 2.0 to 3.0 in terms of obtaininga bicomponent fiber good in spinnability and particularly excellent infiber strength.

The core component may consist of preferably of conventionalmelt-spinnable polyester material. All known types suitable for fibremanufacture may be considered in principle as polyester material. Suchpolyesters consist essentially of components which derive from aromaticdicarbonic acids and from aliphatic diols. Commonly used aromaticdicarbonic acid components are the bivalent residues of benzoldicarbonic acids, particularly of terephthalic acid and isophthalicacid; commonly used diols have 2 to 4 C atoms, ethylene glycol beingparticularly suitable.

Of particular advantage is a polyester material at least 85 mol % ofwhich consists of polyethylene terephthalate. The remaining 15 mol % arethen composed of dicarbonic acid units and glycol units which act asso-called modifiers and which enable the expert to further influence thephysical and chemical properties of the fibres produced in a specificmanner. Examples of such dicarbonic acid units are residues ofisophthalic acid or of aliphatic dicarbonic acid, e.g. glutaric acid,adipinic acid, sabacic acid; examples of diol residues with a modifyingaction are those of longer chain diols, e.g. of propane diol or butanediol, of di- or triethylene glycol or, if available in a small quantity,of polyglycol with a molecular weight of 500 to 2000 g/mol.

Particularly preferable are polyesters which contain at least 95 mol %of polyethylene terephthalate, particularly those of unmodifiedpolyethylene terephthalate. Such polyesters normally have a molecularweight equivalent to an intrinsic viscosity (IV) of 0.5 to 1.4 (dl/g),measured on solutions in dichloroacetic acid at 25° C.

Additives

The polyethylene-based resin (A) forming the sheath portion of the fiberand/or the high-melting point resin (B) forming the core portion of thesame, may be blended with additives, such as coloring material,thermoresistance stabilizer, lubricant, nucleating agent and otherpolymers according to the situation.

The coloring materials applicable to the present invention include, forexample, inorganic coloring materials, such as titanium oxide andcalcium carbonate, and organic coloring materials, such asphthalocyanine.

The thermoresistance stabilizers include, for example, phenol-basedstabilizers such as BHT (2,6-di-t-butyl-4-methylphenol).

The lubricants include, for example, oleic amide, erucic amide andstearic amide. In the present invention, particularly preferably 0.1 to0.5 wt. % of lubricant is blended with the polyethylene-based resin (A)forming the sheath portion, since the bicomponent fiber obtained in theabove manner can have an enhanced fastness to rubbing.

Another group of additives are adhesion promoters which promote adhesionbetween the polyethylene-based resin (A) forming the sheath portion ofthe fiber and or the high-melting point resin (B). Suitable adhesionpromoters are maleic acids (MSA) or maleic acid anhydride (MAH) whichpromote such adhesion. Typical amounts added are from 0.05 to 3% byweight. Most preferred the adhesion promoter is added to thepolyethylene-based resin (A) in the melt during spinning of thebicomponent fiber

Preferably the component ratio by weight of the polyethylene-based resin(A) to the high-melting point resin (B) is in the range of 50/50 to10/90, and in terms of obtaining a fiber excellent in balance ofsoftness and fastness to rubbing, preferably in the range of 50/50 to20/80 and more preferably in the range of 40/60 to 30/70.

When the proportion of the polyethylene-based resin (A) to a bicomponentfiber exceeds 50, there may exist some parts not having been improved infiber strength. On the other hand, when the proportion of thepolyethylene-based resin (A) to a bicomponent fiber is as low as lessthan 10, there may exist some parts poor in both softness and touch inthe obtained fabric.

The area ratio of the sheath portion to the core portion in a crosssection of the core-sheath-type bicomponent fiber according to thepresent invention is generally almost the same as the component ratio byweight described above, and is in the range of 50/50 to 10/90,preferably in the range of 50/50 to 20/80, and more preferably in therange of 40/60 to 30/70.

The core-sheath-type bicomponent fiber according to the presentinvention may be a concentric type one where the circular core portionand the doughnut-shaped sheath portion have the same center in the samecross section of the fiber, the core portion being wrapped up in thesheath portion, or an eccentric type one where the centers of the coreportion and the sheath portion are different from each other. Inaddition, the core-sheath-type bicomponent fiber may be an eccentrictype one where the core portion is partially exposed on the surface ofthe fiber.

For core-sheath-type bicomponent fiber, preferably its fineness is from0.7 to 20 dtex and in terms of obtaining a fiber more excellent insoftness, more preferably from 0.9 to 15 dtex.

Bicomponent Fiber Production

Devices of prior art, with suitable nozzles, may be used formanufacturing bicomponent fiber according to the present invention.

Beside the common core-sheath bicomponent fibres with a core/sheathprofile where the core occupies an eccentric position are also part ofthis invention. These so-called eccentric bicomponent fibres aredescribed in more detail in US 2005/0093197 which forms a part of thisspecification with respect to such eccentric bicomponent design.

The spinning speed for forming the bicomponent fiber according to thepresent invention is typically between 600 and 2,000, preferably between800 and 1,500 m/min.

The escape speed on the nozzle escape surface is matched to the spinningspeed and the drawing ratio so that the fiber finally produced has atitre in the range 0.7 to 20 dtex, preferably from 0.9 to 15 dtex.

The raw materials used for manufacturing the bicomponent fiber accordingto the present invention are independently melted in extruder, etc., andeach molten is extruded through a spinneret with bi-component fiberspinning nozzles constructed to extrude the molten in such a manner asto form a desired structure, e.g. core-sheath, so that the bicomponentfiber is spun out.

The spun bicomponent fiber is then cooled with a cooling fluid, allowedto receive a tensile force by drawing air to have a predeterminedfineness as defined above.

For producing spunbonded Nonwoven fabrics, the fresh spun bicomponentfiber according to the present invention are collected on a collectingbelt to deposit thereon to a predetermined thickness, so that thespunbonded Nonwoven of the bicomponent fiber can be obtained. Thespunbonded bicomponent fiber nonwoven fabric can be consolidatedfurther, e.g. by subjecting the Nonwoven to further entangling, forexample, by the hot embossing process using an embossing roll or byknown needling/hydro entanglement methods.

For producing other Nonwoven, such as wet-laid Nonwoven, air-laidNonwoven and carded Nonwoven, further treatment of the fresh spunbicomponent fiber is required.

Bicomponent Fiber Treatment after Spinning

For producing Nonwoven fabric, such as wet-laid Nonwoven, air-laidNonwoven and carded Nonwoven, further treatments are required afterspinning.

The bicomponent fiber according to the present invention are typicallydrawn with individually different ratios of between 1.2 and 4.0, thedrawing ratios varying by approx. 0.1, i.e. they are 1.2, 1.3; 1.4 . . .to 4.0. The total drawing ratio resulting is between 1.2 and 4.0.

The drawing of the bicomponent fiber takes place at the same temperatureor different temperature of between 40 and 70° C., preferably at 55° C.

Thereafter, the drawn bicomponent fiber can be crimped, typically in astuffer box.

After crimping in the stuffer box the bicomponent fibres are subjectedto heat treatment at up to 100° C., with a holding time from 3 to 20minutes, most preferred from 12 to 15 minutes.

The degree of crimping can be improved using eccentric bicomponentfibers as described above.

Typically, the degree of crimping is expressed as crimp contraction (K1)which is calculated using the EquationK1=(decrimped length−crimped length)/decrimped length [standard climate,20° C.+/−2° C., 60-65% relative air humidity]

The number of crimps is typically given as crimps/cm.

The bicomponent fibres either texturized or not can be cut into staplefibres, then processed into suitable products. Typical staple fiberlength are from 0.2 cm to 15 cm, preferably from 0.2 cm to 8 cm, mostpreferred from 0.3 cm to 6 cm.

For use in wet-laid Nonwoven fabric, the bicomponent fiber according tothe instant invention typically is a non-texturized flat fiber not beingtexturized after spinning. Preferably such flat fibers have a length offrom 0.2 cm to 3 cm, most preferred from 0.3 cm to 2.5 cm.

For use in air-laid Nonwoven fabric the bicomponent fiber according tothe instant invention typically is a texturized fiber. Preferably thecrimp contraction (K1) is from 3 to 7% and the number of crimps is from3 to 6 crimps/cm

For use in carded Nonwoven fabric the bicomponent fiber according to theinstant invention typically is a texturized fiber. Preferably the crimpcontraction (K1) is from 8 to 15% and the number of crimps is from 5 to8 crimps/cm

Thereafter, the bicomponent fibers can be processed into suitableproducts, in particular textile products, preferably hygiene products,hygiene textile fabrics, hygiene non-woven fabrics, nappies, towels orliners and the like, but also into cotton wool buds etc.

As a result of choosing an eccentric core-sheath design such bicomponentfibres are given an additional latent crimp which, during furtherprocessing, can be initiated by heat treatment at temperatures exceedingapprox. 100° C.

Bicomponent Fiber Nonwoven Fabric

Further subjects of the instant invention are Nonwoven fabricscomprising bicomponent fibers as described above.

Due to the nature of the polyethylene-based resin (A) forming at leastpart of the surface of the fiber longitudinally continuously wherein thepolyethylene-based resin (A) is characterized by a Co-monomerDistribution Constant greater than about 45, a recrystallizationtemperature between 85° C. and 110° C., a tan delta value at 0.1 rad/secfrom about 15 to 50, and a complex viscosity at 0.1 rad/second of 1400Pa·sec or less, the processing of the Nonwoven fabrics can significantlyimproved.

The specific polyethylene-based resin (A) allows processing temperaturewhen forming the Nonwoven and later thermo-bonding. Due to the lowermelting point of the polyethylene-based resin (A) which is below 120°C., lower binding temperature and lower energy usage is required. Inaddition, faster line speeds are possible resulting in lower productioncosts. Despite the lower melting point, no significant processingproblems occur during fiber spinning. These and other advantages occurfor example when the bicomponent fiber according to the instantinvention is used in Nonwoven combined with cellulose based fibers whichare extremely heat sensitive. Even a small reduction of theprocessing/thermo-bonding temperature can be of significant commercialadvantage, due to high volumes. In addition, the risk of potential fireis reduced too. Further, a potential heat damage of other materialsblended with the bicomponent fiber according to the instant inventioncan be lowered or even avoided.

Preferred Nonwoven fabrics are (i) wet-laid Nonwoven, (ii) air-laidNonwoven and (iii) carded Nonwoven.

The Nonwoven fabrics according to the instant invention can be blendedwith other fibrous materials.

Preferably, the Nonwoven fabrics according to the instant invention havea basis weight from 10 to 500 g/m². The aforementioned basis weightdepends of the later use.

Preferably, the Nonwoven fabrics according to the instant inventioncomprises the bicomponent fibres either texturized or not and cut intostaple fibres, preferably having a staple fiber length from 0.2 cm to 15cm, more preferred from 0.2 cm to 8 cm, most preferred from 0.3 cm to 6cm.

Preferably, the Nonwoven fabric according to the instant invention is awet-laid Nonwoven fabric comprising the bicomponent fiber according tothe instant invention typically, said bicomponent fiber being anon-texturized flat fiber, preferably having a length of from 0.2 cm to3 cm, most preferred from 0.3 cm to 2.5 cm.

Preferably, the Nonwoven fabric according to the instant invention is anair-laid Nonwoven fabric comprising the bicomponent fiber according tothe instant invention typically, said bicomponent fiber beingtexturized, preferably having a crimp contraction (K1) from 3 to 7% andthe number of crimps from 3 to 6 crimps/cm, preferably having a lengthof from 0.2 cm to 3 cm, most preferred from 0.3 cm to 2.5 cm.

Preferably, the Nonwoven fabric according to the instant invention is acarded Nonwoven fabric comprising the bicomponent fiber according to theinstant invention typically, said bicomponent fiber being texturized,preferably having a crimp contraction (K1) from 8 to 15% and the numberof crimps from 5 to 8 crimps/cm, preferably having a length of from 2 cmto 15 cm, most preferred from 3 cm to 8 cm.

In addition, the Nonwoven according to the instant invention can be aspunbonded Nonwoven comprising continuous filaments or non-continuousfibers, both of the bicomponent type composed of the abovepolyethylene-based resin (A) and high-melting point resin (B).

The formation of the Nonwoven fabric according to the instant inventioncan be made using existing techniques.

The Nonwoven fabrics according to the instant invention can be blendedwith other fibrous and/or particle materials, depending on the intendeduse.

For industrial applications, the Nonwoven fabrics according to theinstant invention comprise other fibrous materials, such as organicand/or inorganic fibrous materials, which may be recycling materials aswell.

The term organic fibrous material comprises beside organic polymerresins also natural fibrous materials. Within the organic polymerresins, all melt-spinnable materials can be used. A particularpreference to melt-spinnable organic polymers such as polyolefins, e.g.polyethylene and/or polypropylene, polyesters, e.g. polyethyleneterephthalate (PET), polybutylene terephthalate (PBT) polynaphthaleneterephthalate (PEN), polytrimethylene terephthalate (PTT), polyamide,e.g. nylon, is given.

For industrial applications, the Nonwoven fabrics according to theinstant invention comprise particle materials, such as inorganicparticle materials, in particular grinding materials.

The term inorganic fibrous material comprises—beside others—those basedon glass and/or minerals, in particular recycled materials.

Industrial applications are filter media or battery separators.

For textile applications, preferably hygiene and/or sanitary products,the Nonwoven fabrics according to the instant invention comprise otherfibrous materials. Preferred fibrous materials are pulp, cellulose,cotton, homo- and copolymers based on polyethylene or polypropylene, inparticular based on recycled materials.

Thereafter, the Nonwoven fabrics according to the instant invention canbe processed into suitable products or processed to form an integralpart of these products, in particular textile products, preferablyhygiene products, hygiene textile fabrics, hygiene non-woven fabrics,disposable diaper, sanitary napkin, nappies, towels or liners and thelike, but also into cotton wool buds etc.

For some textile applications, the Nonwoven fabrics according to theinstant invention in addition to the other fibrous materials cancomprise particle materials, such as super absorber materials, interalia used in disposable diapers.

The Nonwoven fabrics according to the instant invention can be combinedwith other cover or facing layers to provide an even softer touch.Suitable cover or facing layers are melt-blown nonwoven fabrics formedfrom fibers having 1 to 10 μm of diameter.

Test Methods

Density:

Samples that are measured for density are prepared according to ASTM D1928. Measurements are made within one hour of sample pressing usingASTM D792, Method B.

Melt Index:

Melt index, or I₂, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg, and is reported in grams eluted per 10 minutes. I₁₀ ismeasured in accordance with ASTM D 1238, Condition 190° C./10 kg, and isreported in grams eluted per 10 minutes.

DSC Crystallinity:

Differential Scanning calorimetry (DSC) can be used to measure themelting and crystallization behavior of a polymer over a wide range oftemperature. For example, the TA Instruments Q1000 DSC, equipped with anRCS (refrigerated cooling system) and an autosampler is used to performthis analysis. During testing, a nitrogen purge gas flow of 50 ml/min isused. Each sample is melt pressed into a thin film at about 175° C.; themelted sample is then air-cooled to room temperature (˜25° C.). A 3 to10 mg, 6 mm diameter specimen is extracted from the cooled polymer,weighed, placed in a light aluminum pan (ca 50 mg), and crimped shut.Analysis is then performed to determine its thermal properties.

The thermal behavior of the sample is determined by ramping the sampletemperature up and down to create a heat flow versus temperatureprofile. First, the sample is rapidly heated to 180° C. and heldisothermal for 3 minutes in order to remove its thermal history. Next,the sample is cooled to −40° C. at a 10° C./minute cooling rate and heldisothermal at −40° C. for 3 minutes. The sample is then heated to 150°C. (this is the “second heat” ramp) at a 10° C./minute heating rate. Thecooling and second heating curves are recorded. The cool curve isanalyzed by setting baseline endpoints from the beginning ofcrystallization to −20° C. The heat curve is analyzed by settingbaseline endpoints from −20° C. to the end of melt. The valuesdetermined are peak melting temperature (T_(m)), peak recrystallizationtemperature (T_(p)), heat of fusion (H_(f)) (in Joules per gram), andthe calculated % crystallinity for polyethylene samples using Equation2:% Crystallinity=((H _(f))/(292 J/g))×100  (Eq. 2).

The heat of fusion (Hf) and the peak melting temperature are reportedfrom the second heat curve. Peak recrystallization temperature isdetermined from the cooling curve as T_(p).

Dynamic Mechanical Spectroscopy (DMS) Frequency Sweep:

Melt rheology, constant temperature frequency sweeps, were performedusing a TA Instruments ARES rheometer equipped with 25 mm parallelplates under a nitrogen purge. Frequency sweeps were performed at 190°C. for all samples at a gap of 2.0 mm and at a constant strain of 10%.The frequency interval was from 0.1 to 100 radians/second. The stressresponse was analyzed in terms of amplitude and phase, from which thestorage modulus (G′), loss modulus (G″), and dynamic melt viscosity (η*)were calculated.

CEF Method:

Co-monomer distribution analysis is performed with CrystallizationElution Fractionation (CEF) (PolymerChar in Spain) (B. Monrabal et al,Macromol. Symp. 257, 71-79 (2007)). Ortho-dichlorobenzene (ODCB) with600 ppm antioxidant butylated hydroxytoluene (BHT) is used as solvent.Sample preparation is done with autosampler at 160° C. for 2 hours undershaking at 4 mg/ml (unless otherwise specified). The injection volume is300 μl.

The temperature profile of CEF is: crystallization at 3° C./min from110° C. to 30° C., the thermal equilibrium at 30° C. for 5 minutes,elution at 3° C./min from 30° C. to 140° C. The flow rate duringcrystallization is at 0.052 ml/min. The flow rate during elution is at0.50 ml/min. The data is collected at one data point/second.

CEF column is packed by the Dow Chemical Company with glass beads at 125um±6% (MO-SCI Specialty Products) with ⅛ inch stainless tubing. Glassbeads are acid washed by MO-SCI Specialty with the request from the DowChemical Company. Column volume is 206 ml. Column temperaturecalibration is performed by using a mixture of NIST Standard ReferenceMaterial Linear polyethylene 1475a (1.0 mg/ml) and Eicosane (2 mg/ml) inODCB. Temperature is calibrated by adjusting elution heating rate sothat NIST linear polyethylene 1475a has a peak temperature at 101.0° C.,and Eicosane has a peak temperature of 30.0° C. The CEF columnresolution is calculated with a mixture of NIST linear polyethylene1475a (1.0 mg/ml) and hexacontane (Fluka, purum, ≧97.0%, 1 mg/ml). Abaseline separation of hexacontane and NIST polyethylene 1475a isachieved. The area of hexacontane (from 35.0 to 67.0° C.) to the area ofNIST 1475a from 67.0 to 110.0° C. is 50 to 50, the amount of solublefraction below 35.0° C. is <1.8 wt %.

The CEF column resolution is defined as:

${Resolution} = \frac{\begin{matrix}{{{Peak}\mspace{14mu}{temperature}\mspace{14mu}{of}\mspace{14mu}{NIST}\mspace{14mu} 1475a} -} \\{{Peak}\mspace{14mu}{Temperature}\mspace{14mu}{of}\mspace{14mu}{Hexacontane}}\end{matrix}}{\begin{matrix}{{{Half}\text{-}{height}\mspace{14mu}{Width}\mspace{14mu}{of}\mspace{14mu}{NIST}\mspace{14mu} 1475a} +} \\{{Half}\text{-}{height}\mspace{14mu}{Width}\mspace{14mu}{of}\mspace{14mu}{Hexacontane}}\end{matrix}}$The column resolution is 6.0CDC Method:

Co-monomer distribution constant (CDC) is calculated from co-monomerdistribution profile by CEF. CDC is defined as Co-monomer DistributionIndex divided by Co-monomer Distribution Shape Factor multiplying by 100(Equation 1)

$\begin{matrix}\begin{matrix}{{CDC} = \frac{{Comonomer}\mspace{14mu}{Distrubution}\mspace{14mu}{Index}}{{Comonomer}\mspace{14mu}{Distribution}\mspace{14mu}{Shape}\mspace{14mu}{Factor}}} \\{= {\frac{{Comonomer}\mspace{14mu}{Distribution}\mspace{14mu}{Index}}{{Half}\mspace{14mu}{Width}\text{/}{Stdev}}*100}}\end{matrix} & {{Equation}\mspace{14mu} 1}\end{matrix}$

Co-monomer distribution index stands for the total weight fraction ofpolymer chains with the co-monomer content ranging from 0.5 of medianco-monomer content (Cmedian) and 1.5 of Cmedian from 35.0 to 119.0° C.Co-monomer Distribution Shape Factor is defined as a ratio of the halfwidth of co-monomer distribution profile divided by the standarddeviation of co-monomer distribution profile from the peak temperature(T_(p)).

CDC is calculated according to the following steps:

Obtain weight fraction at each temperature (T) (w_(T)(T)) from 35.0° C.to 119.0° C. with a temperature step of 0.200° C. from CEF accordingEquation 2.

Calculate the mean temperature (T_(mean)) at cumulative weight fractionof 0.500 (Equation 3)

Calculate the corresponding median co-monomer content in mole %(Cmedian) at the median temperature (T_(median)) by using co-monomercontent calibration curve (Equation 4).

(3i). Co-monomer content calibration curve is constructed by using aseries of reference materials with known amount of co-monomer content.Eleven reference materials with narrow co-monomer distribution (monomodal co-monomer distribution in CEF from 35.0 to 119.0° C.) with weightaverage Mw of 35,000 to 115,000 (by conventional GPC) at a co-monomercontent ranging from 0.0 mole % to 7.0 mole % are analyzed with CEF atthe same experimental conditions specified in CEF experimental sections.

(3ii). Co-monomer content calibration is calculated by using the peaktemperature (T_(p)) of each reference material and its co-monomercontent. The calibration is: R² is the correlation constant.

Co-monomer Distribution Index is the total weight fraction with aco-monomer content ranging from 0.5*C_(median) to 1.5*C_(median). IfT_(median) is higher than 98.0° C., Co-monomer Distribution Index isdefined as 0.95.

Maximum peak height is obtained from CEF co-monomer distribution profileby searching each data point for the highest peak from 35.0° C. to119.0° C. (if the two peaks are identical then the lower temperaturepeak is selected) Half width is defined as the temperature differencebetween the front temperature and the rear temperature at the half ofthe maximum peak height. The front temperature at the half of themaximum peak is searched forward from 35.0° C., while the reartemperature at the half of the maximum peak is searched backward from119.0° C.

$\begin{matrix}{{Stdev} = \sqrt{\overset{119.0}{\sum\limits_{35.0}}{\left( {T - T_{p}} \right)^{2}*{w_{T}(T)}}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$In the case of a well defined bimodal distribution where the differencein the peak temperatures being equal to or larger than 1.1 times of thesum of half width of each peak, the half-width of the polymer iscalculated as the arithmetic average of the half width of each peak.

The standard deviation of temperature (Stdev) is calculated accordingEquation 5:

An example of co-monomer distribution profile is shown in FIG. 1.

Schematic drawings for obtaining peak temperature, half width and mediantemperature from CEF.

Complex Viscosity (Use Dynamic Melt Viscosity) Also Known as Eta:

The dynamic melt viscosity was calculated from DMS measurements between0.1 Radians/sec to 100 Radians/sec as outlined in section on DMS.

Tan Delta

Tan delta was calculated from G′ and G″ as follows:Tan δ=G″/G′

EXAMPLES

The present invention will be described in further detail with referenceto the examples and comparative examples shown below:

Comparative Comparative Comparative Comparative Example 2 Example 3Example 4 Inventive Example 1 (ASPUN ™ (DOWLEX ™ (ATTANE ™ PropertyExample (PT7009) 6834) 2045) 4606G) MI 15.0 8.7 17.0 1.0 3.0 Density0.920 0.918 0.950 0.920 0.912 Tan delta at 0.1 rad/s 24.4 8.0 44.20 8.6124.71 Eta at 0.1 rad/s (Poise) 968 1836 424 9352 2692 Eta at 100 rad/s225 255 263 1654 900 (Poise) CDC 64.7 114.5 82.8 43.8 37.8 Tp (Peak 9795 115 105 100 recrystallization temp) ° C. (From DSC) Fiber SinningExcellent Medium Excellent Good Good Fibers Stickiness Low Low Low HighHigh Bonding to substrate Excellent low AT high low low at low Temp tempAirlaid process Good Difficult Good low low Fiber Texturizing GoodMedium Good Difficult Difficult

In general for this application, a series of performance attributes areneeded.

First of all, the resin must be capable of forming a fiber in moltenstate at economically viable rates.

Secondly, the resin must be sufficiently good at forming a good bondingonto the core fiber.

Third, the resin must have a low enough melting point for good airlaidprocess as well as for thermal air bonding to other substrates likecellulose.

If the T_(p) is too high, airlaid process is compromised as well as poorthermal air bonding properties. If T_(p) is too low, then sticking offibers becomes an issue.

In fact, a relatively narrow melting range is ideal.

The inventive example in Table 1 is made with the following specificparameters of reaction:

In a two zone tubular high pressure free radical polymerization reactorall of the ethylene is fed into the first zone at a pressure of 2470bars. A mixture of 14.1% tertiary butyl peroxy octoate (by weight) and2.8% ditertiary butyl peroxide (by weight) is fed into the first zone ofthe reactor in an inert solvent typically used for such mixtures. Thefirst zone initiation temperature is 136° C. and the peak temperature ofthe first zone is 310° C. Also to the first zone of the reactor, amixture of methyl ethyl ketone of 1280 volume ppm and propylene of 2.1volume % in an inert solvent is added. To the second reaction zone amixture of 7% (by volume) tertiary butl peroxyoctoate and 7% (by volume)ditertiary butyl peroxide is added, dissolved in an inert solvent. Nochain transfer addition to second reaction zone is done. The inlettemperature to the second reaction zone is 194° C. and the peaktemperature for the second zone is 317° C. The total conversion ofethylene at the outlet of the reactor is 28.7% based on the totalethylene fed at the start of reaction zone 1. The polymer is thendevolatilized to remove unreacted ethylene, inert solvents and otherimpurities and then pelletized. The pellets are used as-is withoutfurther modification.

This material forms the polyethylene-based resin (A) used in thebicomponent fibers according to the instant invention. Since such resin(A) is most important, the properties have been investigated in the formof fibers made only from such resin (A).

Comparative example 1 is a low density polyethylene resin commerciallyavailable from The Dow Chemical Company as LDPE PT7009.

Comparative example 2 is a Ziegler Natta based High Density Polyethylene(HDPE) commercially available as ASPUN™ 6934 resin, also from The DowChemical Company.

Comparative Example 3 is a Ziegler Natta linear low density polyethyleneresin (LLDPE) commercially available from The Dow Chemical Company asDOWLEX™ 2045 resin.

Comparative Example 4 is a Ziegler Natta ultra low density linear lowdensity polyethylene resin (ULLDPE) commercially available from the DowChemical Company as ATTANE™ 4606 resin.

It was found that only comparative examples 1, 2 and the inventiveexample could be made into fibers satisfactorily. While comparativeexample 2 was good in fiber forming due to its high recrystallizationtemperature it did not bond well to fibers at desirable lowtemperatures. Adequate bonding of this comparative example could only bemade at higher temperatures. Comparative examples 3 and 4 were notadequate in fiber forming as their eta 0.1 and eta 100 values were toohigh for high speed economical fiber forming.

While Comparative example 1 was satisfactory in terms of fiber forming,airlaid process as well as heated air bonding, it was inferior toinventive example in texturizing. It was observed that it did not bondwell to the substrate fiber. It was surprisingly found that a goodbonding to the substrate fiber requires that the ratio of G″ and G′ (tandelta) must be in a certain range. If tan delta is too low then thesheathing resin is too elastic and does not provide good bonding, as wasthe case with comparative example 1. If tan delta is too high then thesheating resin is not elastic enough to make a good bonding to thesubstrate fiber. Without good bonding between the sheating resin and thesubstrate fiber no adequate texturizing is obtained.

Additionally, we found that if a resin has a CDC value less than 45,sticking of fibers takes place at a given peak recrystallizationtemperature.

We claim:
 1. A bicomponent fiber composed of a polyethylene-based resin(A) and a high-melting point resin (B) whose melting point is higherthan that of the above polyethylene-based resin (A) by at least 10° C.,the component ratio by weight of the polyethylene-based resin (A) to thehigh-melting point resin (B) being in the range of 50/50 to 10/90, andthe polyethylene-based resin (A) forming at least part of the surface ofthe fiber longitudinally continuously wherein the polyethylene-basedresin (A) is characterized by a Co-monomer Distribution Constant greaterthan about 45, a recrystallization temperature between 85° C. and 110°C., a tan delta value at 0.1 rad/sec from about 15 to 50, a complexviscosity at 0.1 rad/second of 1400 Pa·sec or less, a singledifferential scanning calorimetry (DSC) melting peak with thetemperature range of 85° C. and 110° C., being an ethylene/propylenecopolymer containing more than 50 Mol % of polymerized ethylene monomer,and being obtained through free radical polymerization in the presenceof peroxide and chain transfer agents.
 2. The bicomponent fiber asclaimed in claim 1, wherein the fiber is a core-sheath-type bicomponentfiber, and/or a side-by-side-type bicomponent fiber.
 3. The bicomponentfiber as claimed in claim 1, wherein the polyethylene-based resin (A)has a Co-monomer Distribution Constant in a range of about 45 to about400.
 4. The bicomponent fiber as claimed in claim 1, wherein thepolyethylene-based resin (A) has a Co-monomer Distribution Constant inthe range of about 50 to about
 100. 5. The bicomponent fiber as claimedin claim 1, wherein the polyethylene-based resin (A) has a melt index(measured in accordance with ASTM D 1238, Condition 190° C./2.16 kg) inthe range of from 5 to 25 g/10 min.
 6. The bicomponent fiber as claimedin claim 1, wherein the polyethylene-based resin (A) has a density inthe range of from 0.910 to 0.930 g/cm³.
 7. The bicomponent fiber asclaimed in claim 1, wherein the polyethylene-based resin (A) has a peakrecrystallization temperature in the range of from about 90° C. to about105° C.
 8. The bicomponent fiber as claimed in claim 1, wherein thepolyethylene-based resin (A) having more than about 0.2 long chainbranches/1000 carbons.
 9. The bicomponent fiber as claimed in claim 1,wherein the polyethylene-based resin (A) having a complex viscosity at0.1 rad/second of 1400 Pa·sec or less, and at 100 rad/seconds of 500Pa·sec or less.
 10. The bicomponent fiber as claimed in claim 1, whereinthe polyethylene-based resin (A) having a complex viscosity at 0.1rad/second in the range of 500 to 1200 and at 100 rad/seconds in therange of from 150 to 450 Pa·sec.
 11. The bicomponent fiber as claimed inclaim 1, wherein the polyethylene-based resin (A) having a Tan deltavalue at 0.1 rad/sec from about 15 to
 40. 12. The bicomponent fiber asclaimed in claim 1, wherein the high-melting point resin (B) having amelting point higher than that of the above polyethylene-based resin (A)by at least 20° C.
 13. The bicomponent fiber as claimed in claim 1,wherein the high-melting point resin (B) is a polyolefin, a polyesterresins, or a polyamide resins.
 14. The bicomponent fiber as claimed inclaim 1, wherein the polyethylene-based resin (A) and/or thehigh-melting point resin (B) contain additives selected from the groupconsisting of coloring material, thermoresistance stabilizer, lubricant,nucleating agent and adhesion promoters.
 15. The bicomponent fiber asclaimed in claim 14, wherein the adhesion promoter is maleic acids (MSA)or maleic acid anhydride (MAH), in amounts from 0.05 to 3% by weight.16. The bicomponent fiber as claimed in claim 1, wherein the titer isfrom 0.7 to 20 dtex.
 17. The bicomponent fiber as claimed in claim 1,wherein the fiber is a staple fiber having a length from 0.2 cm to 15cm.
 18. The bicomponent fiber as claimed in claim 1, wherein the fiberis texturized with a crimp contraction (K1) from 3 to 7% and a number ofcrimps from 3 to 6 crimps/cm.
 19. The bicomponent fiber as claimed inclaim 1, wherein the fiber is texturized with a crimp contraction (K1)from 8 to 15% and a number of crimps from 5 to 8 crimps/cm.
 20. Anonwoven comprising the bicomponent fiber as claimed in claim
 1. 21. Thenonwoven as claimed in claim 20, wherein said nonwoven is a wet-laidnonwoven, air-laid nonwoven or carded nonwoven.
 22. The nonwoven asclaimed in claim 20, wherein said nonwoven contains other fibrousmaterials.
 23. The nonwoven as claimed in claim 20, wherein saidnonwoven having a basis weight from 10 to 500 g/m².
 24. The nonwoven asclaimed in claim 20, wherein said bicomponent fiber is a continuousfiber or a staple fibres.
 25. The nonwoven as claimed in claim 20,wherein said nonwoven is a wet-laid nonwoven fabric and said bicomponentfiber being a non-texturized flat fiber having a length of from 0.2 cmto 3 cm.
 26. The nonwoven as claimed in claim 20, wherein said nonwovenis a air-laid nonwoven fabric and said bicomponent fiber beingtexturized with a crimp contraction (K1) from 3 to 7% and a number ofcrimps from 3 to 6 crimps/cm and having a length of from 0.2 cm to 3 cm.27. The nonwoven as claimed in claim 20, wherein said nonwoven is acarded nonwoven fabric and said bicomponent fiber being texturized witha crimp contraction (K1) from 8 to 15% and a number of crimps from 5 to8 crimps/cm, and having a length of from 2 cm to 15 cm.
 28. The nonwovenas claimed in claim 20, wherein said nonwoven further comprises particlematerials.
 29. The nonwoven as claimed in claim 22, wherein said otherfibrous material is an organic and/or inorganic fibrous materials. 30.The nonwoven as claimed in claim 29, wherein said organic fibrousmaterial comprises beside organic polymer resins also natural fibrousmaterials.
 31. The nonwoven as claimed in claim 30, wherein said organicpolymer resins is a melt-spinnable materials.
 32. The nonwoven asclaimed in claim 28, wherein said particle material is an inorganicparticle materials.
 33. The nonwoven as claimed in claim 29, whereinsaid inorganic fibrous material is based on glass and/or minerals. 34.The nonwoven as claimed in claim 29, wherein said organic fibrousmaterial is based on cellulose, cotton, homo- and copolymers based onpolyethylene or polypropylene.
 35. A textile product, in particularhygiene and/or sanitary product, comprising bicomponent fibres asclaimed in claim
 1. 36. A filter media products comprising bicomponentfibres as claimed in claim
 1. 37. A battery separator product comprisingbicomponent fibres as claimed in claim
 1. 38. The nonwoven as claimed inclaim 28, wherein said particle materials being super absorbermaterials.
 39. The nonwoven as claimed in claim 32, wherein saidinorganic particle material is a grinding material.